Railway signaling apparatus



Patented Nov. 9, 1937 UNiT ED STATES PATENT OFFiCE RAILWAY SIGNALING APPARATUS Application May 10, 1935, Serial No. 20,796 Renewed February 5, 1936 30 Claims.

My invention relates to railway signaling apparatus, and more particularly to apparatus of the type involving track circuits.

An object of my invention is to provide novel and improved apparatus for insuring. the release of a track relay when vehicles having wheels which do not make dependable electrical contact with the rails, or which are completely insulated therefrom by non-conducting tread material, enter the section of track with which the relay is associated.

I will describe various forms of apparatus embodying my invention, and will then point out the novel features thereof in claims.

The railway signaling apparatus set forth in my present application. is somewhat similar to that setforth in the two copending applications of Howard A. Thompson, Serial No. 617,137, filed on June 14, 1932, for Apparatus for shunting of track circuits, and Serial No. 629,030, filed on August 16, 1932, for Apparatus for decreasing rail contact resistance, and the said copending applications contain claims which cover broadly certain features of the invention described in my present application.

In the accompanying drawing, Figure 1 shows, in elevation, a rail vehicle provided with equipment cooperative with the track circuits embodying my invention; while Figs. 2, 3, and 4 show 7 different forms of track circuits each embodying my invention and each cooperative with the vehicle-carried equipment shown in Fig. 1. These figures also show a part of the vehicle-carried equipment shown in Fig. l. 7

Similar reference characters refer to similar parts in each of the several views.

Referring first to Fig. 1 of the drawing, the reference character A designates a rail vehicle the wheels of which do not make electrical contact with the rails, because of being equipped with pneumatic tires or any other suitable insulating tread material. Mounted upon car A is a direct current generator G, driven by a motor M. One terminal of generator G makes contact with one rail of the track by means of a brush 3,

and the other terminal of generator G makes contact with the remaining rail by means of a brush 4 through a current limiting resistor Z. Connested across resistor Z is an indicator L, of any suitable type, such as a lamp, for indicating that the current from generator G is being passed into the rails of the track.

The apparatus so far described provides a method of superimposing a direct current from a source aboard a rail vehicle, upon the rails of the track, and for checking that the superimposed current is actually being conducted into the rails. The manner in which such current becomes effective to shunt the track circuit will be apparent from a description of the remaining figures of the drawing.

Referring to Fig. 2, the reference characters i and 2 designate the trafiic rails of a railway track which are provided with insulated rail joints 5 to form a track section EF. The track section E--F is provided with a track circuit, the essential elements of which comprise the traflic rails i and 2, a source of current connected across the traffic rails at one end of the section and a track relay energized by energy taken from the traffic rails at the opposite end of the section.

Considering the source of current for the track circuit of section EF, the secondary winding of a track transformer T has one terminal connected with the rail I by conductor 15; and its other terminal connected with rail 2 through a condenser C, windings I and 6 in series of a reactor R to be referred to later, and a conductor 14. The primary winding of the transformer T is connected with any convenient source of periodic current, such as an alternating current generator, not shown in the drawing. It follows that the transformer T constitutes a source of periodic current from which current is constantly supplied to the traffic rails of the section EF.

The reactor R is preferably of the type commonly known to the art as a three-legged reactor. The windings 6 and l are mounted on the two outer legs, respectively, and are identical and additive as to magnetomotive force and, consequently, substantially no flux created thereby will pass through the center leg. The capacity value-of condenser C and reactance value of the windings Band I are such that they are normally tuned to series resonance for the partic-' ular frequency of the track circuit current. This results in a limiting impedance between the transformer T and the track having a value of approximately the ohmic resistance of the reactor coils 6 and l. Mounted on the center leg of reactor R is a winding 8, also connected across the track rails l and 2, adapted to receive direct current when a vehicle such as A occupies the section. A 'reactance coil I3 is included in the circuit of winding 8 toprevent any appreciable amount of alternating current from flowing through the winding 8, while the: condenser C in the track feed circuit prevents direct current supplied to the winding 8- from passingthrough the windings 6 and I. At the relay end of the track circuit a relay transformer Tl isinterposed between the track relay feed leads i6 and I! and reactor and destroying the resonance between a condenser C and the windings 6 and I. This results in greatly increasing the total limiting impedance between the transformer T and the track, thereby reducing the amount of alternating current energy supplied from the secondary winding of transformer T to the track rails.

Simultaneously, a portion of the direct current applied-to the rails i and 2 flows through the .R and primary winding of he relay transformer Ti,

saturating its core, thereby reducing its impedance and increasing the load on the track circuit at the relay end to further reduce the amount of current supplied to the relay D. As a conse quence, the track relay D will release its front contact to provide a suitable danger signal for following traffic;

A still greater reductionin energy fed to the track relay can be brought about by shunting the primary winding of the relay transformer TI with a condenser. For example, by closing switch S at the relay end of the circuit a condenser C! is connected in multiple with the primary winding of transformer TI. The value of this condenser is so chosen as to produce multiple resonance with the wattless component of the transformer magnetizing current. This reduces the normal load at the relay end of the track circuit to some extent, but greatly increases the load at this point when a vehicle enters the section and reduces the'reactance of the primary winding of transformer Ti by feeding direct current through it.

In Fig. 3 I have shown substantially the same apparatus as shown in Fig. 2, but have shown a modification of the apparatus'at the feed end of the track circuit. In this case the secondary winding of transformer. T is connectedto rail l by conductor 15 and to rail 2 over a path including a current limiting resistor X and conductor [4. Connected across conductors I4 and I5 is a series circuit including winding 8 of the reactor reactance is; across conductors l4 and [5 includes windings 6 and 1 of reactor R and the condenser C. In this form ofthe invention the reactance of windings 6 and I of reactor R, andthe capacity of condenser C are so chosen that normally with the section E'F unoccupied and no direct current flowing through winding 8 of reactor R, the circuit is out of resonance and therefore shunts very little of the current being supplied to the V rails by the secondary of transformer T.

When a vehicle such as A enters the section, the direct current supplied by it to the track rails I and 2 and to winding 8 saturates the iron core 'of the reactor R, thereby reducingits reactance and providing series resonance between windings 6 and! and the condenser C. In this way, the

impedance across, the'track feed leads l4 and I5 while another path.

operate in a slightly different manner, by con'' necting a condenser across the track feed leads. For example, by closing switch SI the auxiliary condenser C2 becomes connected across the track circuit feed leads [4 and I5. With this arrangement the condenser C is merely employed to block the flow of direct current through the Y alternating current coils 6 and I .of the reactor.

The value of condenser C2 is such that with the. track unoccupied multiple resonance normally exists between condenser C2 andthe predominat ing reactance of the circuit including condenser C and the windings 8 and l of the reactor R. This results in very little load being placed across the track circuit fee d leads l4 and with the section unoccupied. When, however, the section becomes occupied by a vehicle which applies direct current to the rails I and 2 and winding 8, I

the multiple resonance formerly existing is vde stroyed, thereby greatly lowering'the impedance across leads l4 and i5 and causing a large reduction in the amount of energy being fed to the track rails and to the track relay.

In Fig. 4 I have shown a variation of'Fig. 3 involving the employment of a reactor R at the relay end of the track circuit, the use of which provides a more sensitive arrangement than those formerly described. tion, the windings t and i of reactor R and condenser C are connectedin series across the track relay feed leads l6 and I1, in multiple with In this form of the inven-' the primary winding of the relay transformer TI;

while the winding 3 and reactance 13 are connected in series across the relay feed leads: it and I7. These connections correspond to those at the feed end of the sectionybut do not include a condenser corresponding to condenser C2. The reactor R normally functions in the same manner as R with switch Si open, and therefore nor- 'mally shunts very little current from the primary winding of transformer Ti. 7

When, however, a vehiclesuch as A enters the section, the direct current fed to winding 8 saturates the core of reactor R thereby reducing its reactance and providing series resonance beand modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In combination with a section of railway I track, a source of periodic current, means for connecting said source'aoross'the trafiic rails of the section comprising a tunedcircuit including a condenser in series with a first winding of a reactor having a magnetizable core, a track relay receiving current from the rails of said section, vehicle-carried means for supplying direct cur.- rent to the trafific rails of said section for detuning said tuned circuit to increase the effective impedance thereof, and a second winding on said reactor arranged to receive direct current from said vehicle to control the flux in the core of the reactor and thereby aid the release ofsaid track relay.

2. In combination with a section of railway track, a source of periodic current, means for connecting said source across the traffic rails or" the section including a first winding of a reactor having a magnetizable core, a track relay receiving current from the rails of said section, means for supplying direct current to the trafiic rails of the section when and only when occupied by a vehicle, and a second winding on said reactor receiving direct current from the rails of said section and varying the permeability of the core of said reactor to control the periodic current supplied to the trafiic rails.

3. In combination with a section of railway track, a source of periodic current, means for connecting said source across the trafiic rails of the section including a first windingof a reactor having a magnetizable core, a track relay receiving current from the rails of said section, a second winding on said reactor, and means for supplying direct current to said second winding when and only when the section is occupied to control the flux in the core of the reactor.

4. In combination with a section of railway track, a source of periodic current, means for connecting said source across the traific rails of the section comprising a tuned circuit including a condenser in series with a first winding of a reactor having a magnetizable core, a second winding mounted on the core of said reactor, means including a vehicle-carried source of direct current for energizing said second winding when a vehicle occupies said section to create a steady magnetic flux for detuning said tuned circuit and increasing the effective impedance thereof so that the voltage of the periodic current supplied across the traflic rails is decreased or increased respectively in accordance with the presence or absence of a train in said section, and an electroresponsive device receiving current from the rails of said section effectively influenced by the periodic current.

5. In combination with a section of railway track, a source of periodic current, a reactor having a magnetizable core provided with a center and two outside legs, means for connecting said source across the trafiic rails of the section comprising a tuned circuit including a condenser in series with a first and a second winding mounted on the outside legs respectively and arranged in such a manner that magnetomotive forces created thereby are additive, a third winding mounted on the center leg, vehicle-carried means including a source of direct current, circuit connections for energizing said third winding from said source of direct current responsive to a train entering said section for detuning said tuned circuit and increasing the effective impedance thereof so that the voltage of the periodic current supplied to the trafiic rails is decreased or increased respectively in accordance with the presence or absence of a train in said section, and an electroresponsive device receiving current from the rails of said section efiectively influenced by the periodic current.

6. In combination with a section of railway track, a source of periodic current, a reactor having a magnetizable core provided with a center and two outside legs, means for connecting said source across the trafiic rails in a circuit including a first and a second winding mounted on the outside legs respectively and arranged in such a manner that magnetomotiveforces created thereby are additive, means includedin the circuit effective to tune the same to series resonance for the particular frequency of the periodic current, a third winding mounted on the center leg of the reactor, vehicle-carried means for supplying unidirectional current to said third winding when the section is occupied to control the permeability of the core of said reactor and in so doing detune the circuit to govern the periodic current supplied to said traffic rails, and a traffic governing electroresponsive device receiving periodic current from the traffic rails.

7. In combination with a section of railway track, a source of periodic current, a reactor having a magnetizable core provided with a center and two outside legs, means for connecting said source across the trafiic rails at one end of the section including afirst and a second winding mounted on the outside legs respectively and arranged in such a manner that magnetomotive forces created thereby are additive, a third winding mounted on the center leg, vehicle-carried means including a source of direct current with circuit connections therefrom for energizing said third winding when and only when the section is occupied to create a steady magnetic flux for determining the reactance of said first and second windings and thereby control the periodic current, and a trafli'c governing electroresponsive device receiving periodic current from the rails of said section.

8. In combination with a section of railway track, a source of periodic current, a reactor having a magnetizable core provided with an auxiliary and two main magnetizable legs, means for connecting said source across the trafiic rails including a first and a second winding mounted on the two main legs respectively, means for connecting a third winding mounted on the auxiliary leg of the reactor across the rails of the section, means including a source of direct current connected across the traffic rails when and only when the section is occupied by a vehicle to energize the third winding by direct current to create a magnetic flux in the core of the reactor for determining the reactance of said first and second windings and thereby control the periodic current, and an electroresponsive device effective- 1y controlled by periodic current received from the rails of said section.

9. In combination with a section of railway track, a source of periodic current, means for connecting said source across the rails of said section including a first winding of a reactor having a magnetizable core, operating means re ceiving current from the rails of said section, means connected across the traffic rails by a ve hicle occupying the section for supplying unidirectional current to the rails of said section when and only when said section is occupied, and a circuit including a second winding of said reactor also connected across the traffic rails effectively influenced by the unidirectional. current for varying the permeability of the core of said reactor to control the periodic current supplied to said operating means.

10. In combination with a section of railway track, a source of periodic current, means for connecting said source across the trafiic rails at one end of the section including a first winding of a reactor having a magnetizable core, means controlled by periodic current received from the rails of said section, vehicle-carried means for supplying the trafiic rails with unidirectional current when and only when said secoccupied.

tion is occupied by't'he vehicle, and means connected across the traffic rails'at said one end of the section including a second winding of said reactor energized by said unidirectionalcurrent andvarying the permeability of the core of said reactor to control the periodic current supplied to the traffic rails. V a

11. In combination with a section of railway track, a track circuit including a source of per odic currentfconnected with the respective rails of the section, a saturation type of reactor for said section having a plurality of windings one of which is included in said circuit and another winding of which is connected across the rails of the section, a condenser for tuning the first-mew 'tioned winding of said reactor to series resonance,

a rail vehicle having a source of direct current thereon, means for conducting current from said source of direct current over the rails of said section through the second Winding of said reactor to saturate the core of said reactor so to detune said tuned winding and thereby change the impedance of said track circuit, andan electroresponsive device effectively controlled by the energy received over the rails of said section.

12. In combination, a section of railway track. a track relay, a track circuit for supplying energy to said track relay including a source of periodic current and the rails of the secttn, reactor having a first winding connected in said circuit at a point between said periodic current source and one rail of the section, means included in said circuit for tuning the circuit to series rose-- nance for the particular frequency of the periodic current from said source, .a second winding on said reactor connected across the of the section, a rail vehicle having a source of direct our- ,rent thereon, and means for conducting current from said direct current source to the rails of said section and through the second winding of said reactor to detune said circuit in rease its impedance whereby the track circuit energy flowing to said track relay is decreased sufiiciently to effect its release.

13. In combination, a section of railway track, a source of periodic track circuit current connected across the rails of said section, a saturation type of reactor having one windin con-- nected between said source and one rail of said section and having a second winding connected across the rails of said section, means included in circuit with said one winding normally reducing the impedance of the path between said source and the rails to substantially the ohmic resistance of the path, vehicle carried means for supplying the second winding of said reactor with direct current when the section is occupied to saturate said reactor and thereby increase impedance of the path, and electroresponsive means controlled by current supplied over the traffic rails of said section.

14. In combination, a section of railway track, a source of periodic current supplying energy'to a track relay for the section over a track circuit including the rails thereof, a first'and second denser included in'the circuit and tuned to series resonance at the frequency of the current from said source, and vehicle carried means supplying energy to a third winding of said reactor .urating the core thereof and destroying the resonance of the track circuit to restrict the supply of energy being fed to the track relay when the section is '15. In combination, a section of railway track,

a source of periodic current supplying energy to -a track relay for the section over the rails thereof, a path for shunting current from said relay including two windings of a saturation type reactor and a condenser. tuned to resonance at the particular frequency of said .source of periodic current only when a third winding of said reactor is energized, and means including a 'vehicle carried source of energy for energizing the third winding of said reactor when the section is occupied.

16. In combination, a section of railway track,

a source of periodic current supplying energy.

to a track relay for the section over the rails thereof, a circuit for shunting current from said relay including two windings of a saturation type reactor and'a condenser connected in multiple across the rails of the section and normally tuned to multiple resonance at the frequency of the periodic current, a third winding on said reactor, and means including a vehicle carried source of current for energizing said third winding to saturate said reactor and thereby detune said circuit. 1'7. In combination with a railway track section, a source of periodic current track circuit energy for said section connected across the rails thereof, a track relay for said section receiving energy from the rails thereof, a reactor of the saturation typev for said section having a first said section to energize said second winding and thereby saturate said reactor to destroy the multiple resonance condition and decrease the impedance of the first winding of said reactor so thatit shunts sufiicient current from'the track relay to eiTect its release.

18. In combination with a railway track section, a source of periodic current track circuit energy for said section connected across the rails thereof, a track relay receiving current from the rails of said section, a reactor of the saturation type for said section having a first winding also connected across the rails of said section, means included in circuit with such winding for normally maintaining its impedance very high so that its presence has very little effect on the current being supplied over the rails, a second winding on said reactor, a rail vehicle having a source of direct current thereon; and means for conducting current from said vehicle-carried source to said second winding, thereby'saturating the reactor and destroying the effect of said first means so that the impedance of the first winding becomes very low when the section is occupied and accordingly reduces the current being fed to the rails of said section.

19. In combination with a section of railway.

ing said relay, a first winding of a second reactor connected in multiple with said means, vehicle-carried means adapted to feed direct current to the traflic rails of the section, and a second winding on each of said reactors arranged to receive current from a vehicle occupying the section to govern the flux in the cores of their respective reactors, to control the supply of energy being fed to said track relay.

20. In combination with a section of railway track, a source of periodic current for said section supplying energy over the rails of said section to a track relay for said section, a reactor of the saturation type for said section having two windings connected in multiple with conductors over which energy is supplied to said track relay, a reactance included in circuit with one of said windings substantially blocking the flow of alternating current therethrough, a condenser in circuit with the other of said windings blocking the flow of direct current therethrough, a rail vehicle having a source of direct current thereon, and means for conducting current from said direct current source to the rails of said section to energize the one of said windings to decrease the impedance of the other winding and thereby shunt sufficient energy from the track relay to effect its release.

21. In combination with a section of railway track, a source of periodic current for the section connected across the rails thereof at one end of the section, a relay transformer having its primary winding connected across the rails of the section at the other end thereof and having its secondary winding included in circuit with a track relay for the section, a condenser connected in multiple with the primary winding of said relay transformer and having a capacity of a value which produces multiple resonance with the wattless component of the relay transformer magnetizing circuit and so reduces the normal load at the relay end of the section, a rail vehicle having a source of direct current thereon, and means for conducting current from said source to the rails of said track to saturate the relay transformer magnetizing circuit and thereby destroy its normal resonant condition so as to greatly increase the load at the relay end of the circuit to efiect release of the track relay.

22. In combination with a section of railway track, a source of periodic current, a saturable reactor having a pair of windings and a magnetizable core, means including one of said windings for connecting said source across the trafl'ic rails of the section, a track relay receiving current from the rails of said section, and means effective when andonly when the section becomes occupied for supplying a saturating current to the other of said windings for controlling the flux in the core of said reactor to thereby control the current received by said track relay.

23. In combination with a section of railway track, a source of periodic current, means including a saturable reactor for connecting said source with the rails of said section, a track relay receiving current from the rails of said section, and means effective when and only when the section becomes occupied for supplying a saturating current to said reactor for controlling the effective impedance thereof to thereby control the current received by said track relay.

24. In combination with a section of railway track, a source of periodic current, means including a saturable reactor for connecting said source with the rails of said section, a track relay receiving current from the rails of said section, and train carried means eifective when and only when the section becomes occupied for supplying a saturating current to said reactor for controlling the effective impedance thereof to thereby control the current received by said track relay.

25. In combination with a section of railway track, a source of periodic current, means including a reactor for connecting said source with the rails of said section, a track relay receiving current from the rails of said section, and means effective when and only when said section becomes occupied for supplying an additional current to said reactor for controlling the effective impedance thereof to thereby control the current received by said track relay.

26. In combination with a section of railway track, a source of periodic current, a tuned circuit including a reactor for connecting said source with the rails of said section, a track relay receiving current from the rails of said secreactor connected with said rails between the,

rails and said relay, and means eifective when and only when said section becomes occupied for supplying a saturating current to said reactor for controlling the effective impedance thereof .to thereby control the current received by said track relay.

28. In combination with a section of railway track, a source of periodic current connected with the rails of said section, a track relay connected across the rails of said section, a reactor connected in parallel with said relay, and means effective when and only when said section becomes occupied for supplying a saturating current to said reactor for controlling the effective impedance thereof to thereby control the current received by said track relay.

29. In combination with a section of railway track, a source of periodic current connected with the rails of said section, a track relay connected across the rails of said section, a reactor connected in parallel with saidrelay, and train carried means effective when and only whenrsaid section becomes occupied for supplying a saturating current to said reactor for controlling the eifective impedance thereof to thereby control the current received by said track relay.

30. In combination with a section of railway track, a track circuit for said section comprising.

a source of periodic current and a track relay each connected across the rails of the section, a saturabie reactor also connected across said rails, and means effective when and only when said section becomes occupied for supplying a saturating current to said reactor for controlling the effective impedance thereof to thereby control the current received by said track relay.

ROBERT M. GILSON. 

